1. Field of the Invention
The present invention relates to a voltage controller which controls an output voltage of an alternator mounted on a vehicle such as a passenger car, a truck or the like.
2. Description of Related Art
An alternator mounted on a vehicle has a voltage controller, and the controller has an integrated circuit (IC) chip acting as a control circuit to control an output voltage of the alternator. This IC chip has recently been highly integrated and downsized. For example, Published Japanese Patent First Publication No. 2003-244913 discloses a voltage controller having a small-sized IC chip. In this Publication, the IC chip is sealed with an insulator made of resin or the like. Lead wires extending from the IC chip are protruded from the insulator. The controller further has a terminal holding body and connecting terminals held in the holding body. Portions of the terminals are protruded from a surface of the holding body and are, respectively, connected with the lead wires. The terminals are disposed to be aligned with one another along a single straight line on the surface of the holding body. The IC chip is electrically connected with a rectifier and a brush apparatus of the alternator and an external control unit through the connecting terminals and the lead wires.
However, as the IC chip is downsized, intervals among the lead wires of the IC chip are narrowed. In this case, intervals among the terminals connected with the lead wires are also inevitably narrowed. Therefore, an on-surface distances (i.e., creepage distance) between two terminals adjacent to each other cannot be sufficiently set at a large value. In this case, when the terminals are covered with water or the like, the terminals are short-circuited so as to leak an electric current of one terminal to another terminal. Further, corrosions and disconnections among the terminals occur due to leakage of electric currents among the terminals. In this specification, an on-surface distance between two terminals adjacent to each other is defined as a distance on the surface of the holding body from which the terminals are protruded.